Becoming a parent is one hell of a big change. "No shit, Sherlock," I hear you say.
Seriously though. It is a HUGE change. If you previously were fine with living in an organised chaos, you will now have to get used to keeping the organised chaos out of toddler's reach. If you hated Xmas and the decorations and carols and all that jazz, you're screwed. You will now be expected to decorate your house, go overboard with gifts, set up Xmas stockings, suffer in silence and mentally envision the tragic death of all those people responsible for teaching your child all those horrible Xmas Carols. If you hated the idea of spending a day at the beach.. again, you're screwed. You will get to spend literally, a day at the beach, in the company of endless beach toy supplies, sun block, water mattresses, swimming aids, snorkeling gear, and more likely than not, a tantrum at the end of the day thrown as loudly as possible by an overtired child who doesn't want the day to end.
You will also get to annually be around dozens of screaming, sticky children, frantically trying to prevent them from destroying your house. Gods forbid you have a clown phobia! You'll be bound to be forced to face your phobia, for your child's sake. And, you will have to succumb into being The One To Sing The First Note Of 'Happy Birthday'. Over and over again.
The best part of it all? Getting to not only listen to the aforementioned annoying songs when they are justified, but also listening to them over and over again all year round.